Philip Johnston has been with the Daily Telegraph for more than 20 years. He is currently assistant editor and leader writer and was previously home affairs editor and chief political correspondent.

A 'rich tax' levied on the middle classes

Full coverage of UK politicsAs property prices tumble, the impact of inheritance tax on low income households with high property values will be lessened and, in a letter to the Guardian today, members of the so-called "progressive Left" have criticised the Government for its decision to increase the threshold for the combined allowances for married couples and those in civil partnerships to Â£600,000, rising to Â£700,000 in 2010.Â The move was made last autumn in response to the Tory decision to increase the individual threshold to Â£1m.

It was unpopular on the Left, and the Guardian letterÂ says there should be no further concessions in this area. "The core mission that should underpin progressive politics is that we should not inherit our life chances at birth: our opportunities should depend on our efforts, not who our parents are."

But most people facing inheritance taxes are not the landed gentry but ordinary hard-working middle class families drawn into paying duties that were originally intended to prevent the aristocracy building up vast estates. There is a moral argument against inheritance taxes that the Left simply never understands (just as it does not for other taxes.)

The letter states that only a small proportion of householders paid inheritance tax last year but that is merely to point out that not everyone dies. Under IHT, many people become higher-rate taxpayers for the first time only after their deaths.

It is a tax on the prudent and family-minded, falling principally on the middle classes, since the rich can always find ways to avoid it; it involves being taxed when you die on wealth that was taxed while being accumulated in life, and therefore is a double whammy. It discourages wealth creation and retention.

Even with the Government's transferable exemption, Britain now still has one of the most punitive inheritance tax regimes in the developed world. The tax has been abolished in Australia, New Zealand and Canada for many years and America, which has a $1 million (Â£633,000) tax-free allowance, plans to phase out federal estate duties by 2010, though individual states levy their own taxes.

In Britain since 1997, the number of people facing potential inheritance tax bills has risen dramatically simply because they own their home, and is set to grow further unless there is a monumental crash in house prices

Inheritance tax is a wealth tax that is no longer levied on the wealthy. While the middle classes have increasingly found the tax virtually unavoidable, it is effectively a voluntary burden on the seriously rich, who can hand over art treasures to the nation in lieu of tax or shield their assets in offshore tax havens beyond the means of most of us.